CN103543334A - Phase difference measurement device and method based on FFT - Google Patents
Phase difference measurement device and method based on FFT Download PDFInfo
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Abstract
The invention provides a phase difference measurement device and method based on FFT, and belongs to the technical field of signal processing. The phase difference measurement device and method are especially suitable for situations when phase differences need to be measured at high precision such as a phase type laser distance-measurement system. The measurement device is a hardware circuit formed by a processor chip and a peripheral circuit of the processor chip. The measurement method includes the steps that synchronous analog-to-digital conversion is carried out on two paths of signals which have the same frequency and a phase difference, a sampling frequency is controlled through a timer, two sets of analog-to-digital conversion results obtained continuously are stored in a processor RAM through a DMA controller, floating point complex number FFT operations are carried out on the two sets of the data to obtain digital frequency spectrums of the signals, the phases of spectral lines of corresponding signal frequencies in the two sets of the digital frequency spectrums are calculated and the phase difference of the two paths of the analog signals is obtained after the phases of the spectral lines are subtracted. According to the phase difference measurement device and method, phase difference measurement is carried out, and the phase difference measurement device and method have the prominent advantages of being low in hardware density and high in phase measurement precision.
Description
Technical field
The invention provides a kind of based on FFT(Fast Fourier Transform (FFT)) phase difference measuring apparatus and method, belong to signal processing technology field, being specially adapted to phase-shift laser range-finder etc. needs the poor occasion of high-precision phase measurement.
Background technology
The method of measuring-signal phase differential can be divided into time domain method and frequency domain method conventionally.Time domain method need to be adjusted into square-wave signal by mimic channel by measured signal, then two paths of signals is adjusted, output is with the square-wave signal with certain dutycycle of phase information, and then with high frequency, survey chi signal it is filled, by the high-frequency signal of filling is counted, finally draw phase differential result.The method is had relatively high expectations to mimic channel, need to nurse one's health out high-quality square-wave signal.Simultaneously for guaranteeing that phase-measurement accuracy is higher than per mille, it is tens even up to a hundred million that the modulation frequency of selecting generally will reach, and more increased hard-wired difficulty.
Phase difference measurement also can be carried out at frequency domain, need to carry out analog to digital conversion to simulating signal, then carries out time domain to the conversion of frequency domain.Due to reasons such as spectral leakage and fence effects, also need to carry out the survey phase result that further Spectrum Correction just can obtain degree of precision, algorithm is comparatively complicated.
Summary of the invention
The object of the invention is the shortcoming existing in order to solve existing survey phase technology, a kind of phase difference measuring apparatus and the method based on FFT providing is provided and known feature for being similar to the measured signal frequency that phase-shift laser range-finder has.
The object of the invention is to be achieved through the following technical solutions.
A kind of phase difference measuring apparatus of the present invention, this device is hardware circuit, hardware circuit comprises processor chips and peripheral circuit;
Described processor chips need meet the following conditions: built-in two analog to digital conversion kernels independently, built-in timer module, built-in DMA(direct memory access) controller, built-in Float Point Unit, ram in slice (random access memory) is not less than 50kB, Flash(flash memory in sheet) be not less than 50kB.
Described peripheral circuit comprises power configuration circuit, mode of operation configuration circuit, frequency source, reference voltage configuration circuit, program debug and download circuit, two-way analog signal interface and surveys phase result display circuit.
Described power configuration circuit provides power supply for processor chips, and power configuration circuit comprises the decoupling capacitor being connected between processor chips power pins and ground;
Described mode of operation configuration circuit is connected to power supply or ground by resistance by processor chips pin, by processor chip configuration, is required mode of operation;
Described frequency source is passive high-precision crystal oscillator;
Described reference voltage configuration circuit provides reference voltage and reference voltage is carried out to filtering noise reduction process for analog to digital conversion;
Described program debug and download circuit are for the treatment of on-line debugging and the download of device program.
Described two-way analog signal interface accesses simulating signal to be measured 1 and simulating signal 2;
Described survey phase result display circuit is used for showing survey phase result.
A kind of method for measuring phase difference of the present invention, described method realizes based on said apparatus, and concrete steps are as follows:
1) system clock frequency source is set to external high frequency crystal oscillator, by inner frequency multiplication, system clock is configured to higher frequency;
2) open described two analog to digital conversion kernels independently, be configured to synchronous mode, two-way analog input is carried out to strict synchronous sampling conversion, sampling trigger source is set to timer and overflows event, and the object of sample frequency is accurately controlled in realization by timer;
3) configure described timer module, set counter register value, overflow rear generation event, trigger analog-to-digital conversion module and sample; System clock is counted, by setting the value in counter register, controlled and overflow frequency, thereby realize the object of accurately controlling analog-to-digital conversion module sample frequency; Set sample frequency and be 2 integral number power of measured signal frequency doubly, make to carry out the packet of base-2-FFT containing an integer cycle of sinusoidal signal to be measured;
4) configure described dma controller, make its connection mode number conversion result register and internal RAM, realize the result data that two analog to digital conversion kernels are obtained and be directly sent in real time the array space of opening up in advance in RAM;
5) above-mentioned analog to digital conversion result data carries out before 1024 floating-point plural number FFT computing, it is carried out to pre-service, phase measurement each time, analog to digital conversion is exported the transformation result of two groups 1024 altogether, for carrying out plural FFT computing, open up in addition the array of the floating-point format of two 2048, above-mentioned data are deposited respectively in to the even address of this array, and at its place, odd address, deposit imaginary part zero in; Plural FFT functional parameter is set, is configured to base-2,1024 points, positive sequence Output rusults; Above-mentioned pretreated data are carried out to plural FFT computing, and result deposits raw address in;
6) digital spectrum that above-mentioned FFT operation result is measured signal, binding signal frequency, sample frequency and FFT computing are counted, calculate the position of measured signal frequency in the above-mentioned array of depositing digital spectrum, from the array of above-mentioned two 2048, extract respectively real part and the imaginary part of this frequency spectral line;
7) respectively above-mentioned two pairs of real parts and imaginary part are carried out to computing, extract phase information, first by imaginary part divided by real part, then result is carried out to arctangent cp cp operation, obtain the phase information of two paths of signals on this Frequency point;
8) due to the restriction of arctan function codomain, according to the symbol of spectrum results real part and imaginary part, phase information obtained above is carried out to quadrant location, obtain the real phase information of sinusoidal signal to be measured, and then the phase place of two paths of signals is subtracted each other, finally obtain needed phase information.
9) phase information is shown by surveying phase result display circuit.
Beneficial effect
Processor chips and a small amount of peripheral circuit thereof of device of the present invention based on a built-in required function module realized, and hardware density is lower; By set sample frequency be measured signal frequency 2 integral number power doubly, make to carry out the packet of base-2-FFT containing an integer cycle of sinusoidal signal to be measured, avoided the factors such as spectral leakage and fence effect on surveying the impact of phase result, made algorithm realize simple and precision is higher.
Accompanying drawing explanation
Fig. 1 is a kind of phase difference measuring apparatus circuit diagram based on FFT of the present invention;
Fig. 2 is a kind of method for measuring phase difference principle schematic based on FFT of the present invention.
Embodiment
Below in conjunction with drawings and Examples, the present invention will be further described.
Embodiment
Measured signal is the sinusoidal signal that the dephased frequency of two-way band is 10kHz, with device and method provided by the invention, carries out phase difference measurement.
As shown in Figure 1, a kind of phase difference measuring apparatus, described device is: the hardware circuit consisting of a processor chips and peripheral circuit thereof.
Described a processor chips model is STM32F407VG, based on Cortex-M4 kernel, built-in two analog to digital conversion kernels independently, built-in timer module, built-in dma controller, built-in Float Point Unit, dominant frequency reaches 168MHz, monocycle DSP instruction, ram in slice is 112kB, in sheet, Flash is 1MB.
Described peripheral circuit comprises power configuration circuit, mode of operation configuration circuit, frequency source, reference voltage configuration circuit, program debug and download circuit, two-way analog signal interface and surveys phase result display circuit.
Described power configuration circuit provides power supply for processor chips, and power configuration circuit comprises the decoupling capacitor being connected between processor chips power pins and ground;
Described mode of operation configuration circuit is connected to power supply or ground by resistance by processor chips pin, by processor chip configuration, is required mode of operation;
Described frequency source is passive high-precision crystal oscillator;
Described reference voltage configuration circuit provides reference voltage and reference voltage is carried out to filtering noise reduction process for analog to digital conversion;
Described program debug and download circuit are for the treatment of on-line debugging and the download of device program.
Described two-way analog signal interface accesses simulating signal to be measured 1 and simulating signal 2;
Described survey phase result display circuit is LCD liquid crystal display circuit, for showing, surveys phase result.
As shown in Figure 2, a kind of method for measuring phase difference, described method realizes based on said apparatus, and concrete steps are as follows:
1) system clock frequency source is set to external high frequency crystal oscillator, by inner frequency multiplication, system clock is configured to 168MHz;
2) open described two analog to digital conversion kernels independently, be configured to synchronous mode, two-way analog input is carried out to strict synchronous sampling conversion, 12bits resolution, sampling trigger source is set to timer 1 and overflows event, realizes the object of accurately being controlled sample frequency by timer;
3) configure described timer module, setting counter register value is 524, and overflowing frequency is 168MHz/524=320kHz, overflows rear generation event, triggers analog-to-digital conversion module and samples, and realizing sample frequency is 320kHz; 10kHz sinusoidal signal is sampled, 1024 32 complete cycles that point comprises this signal, thus avoid after FFT the factor such as spectral leakage and fence effect on surveying the impact of phase result;
4) configure described dma controller, enable passage 0, peripheral hardware address is analog to digital conversion result register address, memory address is predefined array first address, direction is for being set to internal memory from outward, transmit 1024 of 32 bit wide data, its high 16 is ADC1 transformation result, and low 16 is ADC2 transformation result;
5) open up in addition the array of the floating-point format of two 2048, above-mentioned data are deposited respectively in to the even address of this array, and at its place, odd address, deposit imaginary part zero in; Plural FFT functional parameter is set, is configured to base-2,1024 points, positive sequence Output rusults; Above-mentioned pretreated data are carried out to plural FFT computing, and result deposits raw address in;
6) digital spectrum that above-mentioned FFT operation result is measured signal, signal frequency is that 10kHz, sample frequency are 320kHz, it is 1024 that FFT computing is counted, the frequency resolution of FFT is: 320kHz/512=625Hz, and 10kHz/625Hz=16, the 17th of digital spectrum the point is corresponding measured signal, extracts respectively real part and the imaginary part of this frequency spectral line from two arrays;
7) respectively above-mentioned two pairs of real parts and imaginary part are carried out to computing, extract phase information, first by imaginary part divided by real part, then result is carried out to arctangent cp cp operation, obtain the phase information of two paths of signals on this Frequency point;
8) due to the restriction of arctan function codomain, according to the symbol of spectrum results real part and imaginary part, phase information obtained above is carried out to quadrant location, obtain the real phase information of sinusoidal signal to be measured, and then the phase place of two paths of signals is subtracted each other, finally obtain needed phase information.
9) phase information is shown by LCD liquid crystal display circuit.
Claims (9)
1. a phase difference measuring apparatus, is characterized in that: this device is hardware circuit, and hardware circuit comprises processor chips and peripheral circuit;
Described processor chips need meet the following conditions: built-in two analog to digital conversion kernels independently, built-in timer module, built-in DMA(direct memory access) controller, built-in Float Point Unit, ram in slice (random access memory) is not less than 50kB, Flash(flash memory in sheet) be not less than 50kB;
Described peripheral circuit comprises power configuration circuit, mode of operation configuration circuit, frequency source, reference voltage configuration circuit, program debug and download circuit, two-way analog signal interface and surveys phase result display circuit.
2. a kind of phase difference measuring apparatus according to claim 1, is characterized in that: power configuration circuit provides power supply for processor chips, and power configuration circuit comprises the decoupling capacitor being connected between processor chips power pins and ground.
3. a kind of phase difference measuring apparatus according to claim 1, is characterized in that: mode of operation configuration circuit is connected to power supply or ground by resistance by processor chips pin, by processor chip configuration, is required mode of operation.
4. a kind of phase difference measuring apparatus according to claim 1, is characterized in that: frequency source is passive high-precision crystal oscillator.
5. a kind of phase difference measuring apparatus according to claim 1, is characterized in that: reference voltage configuration circuit provides reference voltage and reference voltage is carried out to filtering noise reduction process for analog to digital conversion.
6. a kind of phase difference measuring apparatus according to claim 1, is characterized in that: program debug and download circuit are for the treatment of on-line debugging and the download of device program.
7. a kind of phase difference measuring apparatus according to claim 1, is characterized in that: two-way analog signal interface accesses simulating signal to be measured 1 and simulating signal 2.
8. a kind of phase difference measuring apparatus according to claim 1, is characterized in that: survey phase result display circuit and be used for showing survey phase result.
9. a method of utilizing the device described in claim 1 to carry out phase difference measurement, is characterized in that concrete steps are as follows:
1) system clock frequency source is set to external high frequency crystal oscillator, by inner frequency multiplication, system clock is configured to higher frequency;
2) open described two analog to digital conversion kernels independently, be configured to synchronous mode, two-way analog input is carried out to strict synchronous sampling conversion, sampling trigger source is set to timer and overflows event, and the object of sample frequency is accurately controlled in realization by timer;
3) configure described timer module, set counter register value, overflow rear generation event, trigger analog-to-digital conversion module and sample; System clock is counted, by setting the value in counter register, controlled and overflow frequency, thereby realize the object of accurately controlling analog-to-digital conversion module sample frequency; Set sample frequency and be 2 integral number power of measured signal frequency doubly, make to carry out the packet of base-2-FFT containing an integer cycle of sinusoidal signal to be measured;
4) configure described dma controller, make its connection mode number conversion result register and internal RAM, realize the result data that two analog to digital conversion kernels are obtained and be directly sent in real time the array space of opening up in advance in RAM;
5) above-mentioned analog to digital conversion result data carries out before 1024 floating-point plural number FFT computing, it is carried out to pre-service, phase measurement each time, analog to digital conversion is exported the transformation result of two groups 1024 altogether, for carrying out plural FFT computing, open up in addition the array of the floating-point format of two 2048, above-mentioned data are deposited respectively in to the even address of this array, and at its place, odd address, deposit imaginary part zero in; Plural FFT functional parameter is set, is configured to base-2,1024 points, positive sequence Output rusults; Above-mentioned pretreated data are carried out to plural FFT computing, and result deposits raw address in;
6) digital spectrum that above-mentioned FFT operation result is measured signal, binding signal frequency, sample frequency and FFT computing are counted, calculate the position of measured signal frequency in the above-mentioned array of depositing digital spectrum, from the array of above-mentioned two 2048, extract respectively real part and the imaginary part of this frequency spectral line;
7) respectively above-mentioned two pairs of real parts and imaginary part are carried out to computing, extract phase information, first by imaginary part divided by real part, then result is carried out to arctangent cp cp operation, obtain the phase information of two paths of signals on this Frequency point;
8) due to the restriction of arctan function codomain, according to the symbol of spectrum results real part and imaginary part, phase information obtained above is carried out to quadrant location, obtain the real phase information of sinusoidal signal to be measured, and then the phase place of two paths of signals is subtracted each other, finally obtain needed phase information;
9) phase information is shown by surveying phase result display circuit.
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN104360159A (en) * | 2014-11-19 | 2015-02-18 | 国网浙江余姚市供电公司 | Nuclear phase method and device |
| CN106230752A (en) * | 2015-06-02 | 2016-12-14 | 中兴通讯股份有限公司 | A kind of method of sampling and network chip |
| CN106814339A (en) * | 2015-11-27 | 2017-06-09 | 西门子(深圳)磁共振有限公司 | Phase information acquisition methods, system and magnetic resonance imaging system |
| CN106941330A (en) * | 2017-05-19 | 2017-07-11 | 信利光电股份有限公司 | A kind of method and system of control motor vibrations |
| CN106941335A (en) * | 2017-03-10 | 2017-07-11 | 信利光电股份有限公司 | The implementation method and device of a kind of single vibration |
| CN107505053A (en) * | 2017-08-23 | 2017-12-22 | 浙江工业大学 | A kind of sinusoidal signal method for measuring phase difference based on FPGA and FFT technique |
| CN107561360A (en) * | 2017-08-23 | 2018-01-09 | 浙江工业大学 | A kind of sinusoidal signal method for measuring phase difference based on FPGA and subtraction circuit |
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| CN109387697A (en) * | 2018-11-20 | 2019-02-26 | 国网甘肃省电力公司电力科学研究院 | Wireless phase measurement device, method for synchronizing time and wireless Method for Phase Difference Measurement |
| CN112583497A (en) * | 2020-12-16 | 2021-03-30 | 重庆两江卫星移动通信有限公司 | Phase measurement device and method based on real number single-tone signal |
| CN112600558A (en) * | 2020-12-22 | 2021-04-02 | 江苏金帆电源科技有限公司 | Analog-to-digital conversion linearity correction method and device |
| CN112782451A (en) * | 2020-12-22 | 2021-05-11 | 中国科学院合肥物质科学研究院 | Phase analysis method, device and system based on time domain |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN104360159A (en) * | 2014-11-19 | 2015-02-18 | 国网浙江余姚市供电公司 | Nuclear phase method and device |
| CN106230752A (en) * | 2015-06-02 | 2016-12-14 | 中兴通讯股份有限公司 | A kind of method of sampling and network chip |
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| CN106941330A (en) * | 2017-05-19 | 2017-07-11 | 信利光电股份有限公司 | A kind of method and system of control motor vibrations |
| CN107561360A (en) * | 2017-08-23 | 2018-01-09 | 浙江工业大学 | A kind of sinusoidal signal method for measuring phase difference based on FPGA and subtraction circuit |
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| CN107666349B (en) * | 2017-08-23 | 2020-07-28 | 中国科学院苏州生物医学工程技术研究所 | High-precision multichannel high-speed data transmission link isometric detection method |
| CN107505053A (en) * | 2017-08-23 | 2017-12-22 | 浙江工业大学 | A kind of sinusoidal signal method for measuring phase difference based on FPGA and FFT technique |
| CN109387697A (en) * | 2018-11-20 | 2019-02-26 | 国网甘肃省电力公司电力科学研究院 | Wireless phase measurement device, method for synchronizing time and wireless Method for Phase Difference Measurement |
| CN113030567A (en) * | 2019-12-25 | 2021-06-25 | 航天科工惯性技术有限公司 | Frequency measurement method and device based on single chip microcomputer |
| CN112583497A (en) * | 2020-12-16 | 2021-03-30 | 重庆两江卫星移动通信有限公司 | Phase measurement device and method based on real number single-tone signal |
| CN112600558A (en) * | 2020-12-22 | 2021-04-02 | 江苏金帆电源科技有限公司 | Analog-to-digital conversion linearity correction method and device |
| CN112782451A (en) * | 2020-12-22 | 2021-05-11 | 中国科学院合肥物质科学研究院 | Phase analysis method, device and system based on time domain |
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